#!/usr/bin/env python3
# -*- coding=utf-8 -*-
# 题目：画图，学用rectangle画方形。


def f1():
    from tkinter import Canvas
    from tkinter import Tk

    root = Tk()
    root.title("Canvas")
    canvas = Canvas(root, width=400, height=400, bg="yellow")
    x0 = 263
    y0 = 263
    y1 = 275
    x1 = 275
    for i in range(19):
        canvas.create_rectangle(x0, y0, x1, y1)
        x0 -= 5
        y0 -= 5
        x1 += 5
        y1 += 5

    canvas.pack()
    root.mainloop()


f = f1
if __name__ == "__main__":
    f()
